A geological trench is formed by a crustal block bounded by normal faults and has dropped in relation to its surroundings. Ditches occur as a result of tectonic strain in zones of weakness in the earth's crust, always together with tectonic Horsten ( prominent clods ).
At times, the sedimentary rocks that fill the trenches, harder than the rocks of the adjacent clumps. Thus it may happen that the trenches, contrary to expectations from the erosion are excised as striking elevations, while the clumps morphological valleys form (relief reversal).
Extensive grave systems are often referred to as rift zones.
- Great African rift Jordan Valley
- East African rift